flagger

package main

import (
	"bytes"
	"flag"
	"fmt"
	"time"

	"codeberg.org/clambin/go-common/flagger"
)

func main() {
	type config struct {
		String    string        `flagger.usage:"a string"` // flagger.usage sets usage text
		Int       int           `flagger.usage:"an int"`
		Float     float64       `flagger.usage:"a float"`
		Bool      bool          `flagger.name:"boolean" flagger.usage:"a bool"` // flagger.name overrides the name
		Duration  time.Duration `flagger.usage:"a duration"`
		Skipped   bool          `flagger.skip:"true"`
		SubStruct struct {
			String string `flagger.usage:"a substring"`
			Int    int    `flagger.name:"int" flagger.usage:"another int"`
		} `flagger.name:"sub"`
	}
	// in a real application, we would use flag.CommandLine directly
	f := flag.NewFlagSet("", flag.PanicOnError)
	flagger.SetFlags(f, &config{String: "foo", Int: 42, Float: 3.14, Bool: true, Duration: 1 * time.Second})
	var output bytes.Buffer
	f.SetOutput(&output)
	f.Usage()
	fmt.Println(output.String())

}

Output:

Usage:
  -boolean
    	a bool (default true)
  -duration duration
    	a duration (default 1s)
  -float float
    	a float (default 3.14)
  -int int
    	an int (default 42)
  -string string
    	a string (default "foo")
  -sub.int int
    	another int
  -sub.string string
    	a substring